New Addition - Various Plumbing Questions
All-
The help I've received on this forum is beyond compare. You guys really make it possible for someone to figure this stuff out. Thanks so much.
We are in the planning stages of a relatively small, but plumbing heavy addition to our home. The space is 10' L x52"W and will span three floors. I've decided to do as much of the work myself as is possible, reasonable and legal, including drawing up the plans for the permit. I am in this process and would like some guidance as I make some of decisions. Would really appreciate any help possible. For what it is worth, I live in Washington, DC where we are subject to the following codes/regulations:
2000 International Building Code
2000 International Plumbing Code
2000 International Residential Code
So, my initial questions, somewhat varied in scope are:
1) We are planning to install a powder room in one part of the addition. Because of how the addition ties into the home the dimensions are approximately 38"L x 52" W. Is this even possible, pursuant to code? Are there really low profile toilets? We plan on using a pocket door, so it will eliminate that intrusion and we've found a 16"x16" vanity, which should help. Any advice on layout? What are suggested clearances for a)comfort and b) code?
2) I am trying to figure out the best way to tie the new addition into the house's plumbing. The addition will contain a powder room (toilet and lav) and a full bath(tub/shower, lav and toilet). My thinking is to run a 3" stack up the side of the addition that would service both the powder room and the full bath, venting out the roof. There seems to be two options to tie this 3" stack into the house's plumbing.
Option 1 - Run it in a soffit along my basement ceiling, tying into the house's main cast iron stack. The stack is at least 3", but could be 4" (as an aside, how can I figure that out?). That would involve a straight run of about 13' where it would have to 90 and then run another 4' or so to the stack. Currently this main stack services just one bathroom (tub/shower, lav and toilet).
Option 2- We could run the 3" addition stack straight into the ground, run it through the house's foundation, and tie it into a 3" cast iron drain line under the slab of my finished basement. This drain line services a full bath (tub/shower, lav and toilet, as well as a washing machine and bar sink).
What are your opinions on these two options? Obviously Option 2 would be cleaner (no soffit), but much more disruptive. I figure overall the soffit would have be about 6 or 7" to accommodate the slope of the pipe 1/4" per foot, right?) Any other suggestions?
I am sure there are many more questions to come, but for now, this would really help get me oriented.
Thanks so much!